1. Field of the Invention
The present invention relates to a fixing construction for a pipe joint. The invention relates, more particularly, to a pipe joint fixing construction including a pipe joint body within which a fluid transport pipe is connected and engaged in a sealed state via an elastic seal, a press ring fitted on the fluid transport pipe, the press ring being peripherally divided to provide a plurality of press-ring segments, a fastener means for fasting each press-ring segment to a connecting portion of the pipe joint body along a pipe axis direction, a retainer member interposed between an outer peripheral face of the fluid transport pipe and an inner peripheral face of the press ring, the retainer member being capable of radially biting into the outer peripheral face of the fluid transport pipe, and a cam surface formed in the inner peripheral face of the press ring, the cam surface being operable to reduce the retainer member radially with a relative movement between the pipe joint body and the press ring along the pipe axis direction in association with a fastening operation by the fastener means.
2. Description of the Related Art
With the pipe joint fixing construction of the above-noted type, when the pipe joint portion and the fluid transport pipe are subjected to an external force in a mutually pulling-out direction due to an earthquake, a differential settlement or the like, the outer peripheral face of the retainer member biting into the outer peripheral face of the fluid transport pipe and the cam surface formed in the inner peripheral face of the press ring come into contact with each other progressively, so that the retainer member is reduced or deformed radially and the bite-in amount thereof increases correspondingly. As a result, a joint failure or the like due to inadvertent removal of the fluid transport pipe from the pipe joint body or an excessive relative movement along the pipe axis direction between the pipe joint body and the fluid transport pipe may be advantageously restricted.
FIG. 9 shows a conventional pipe joint fixing construction having such advantage as described above. As shown, in this construction, connecting faces 40 of a connecting portion 5 of the pipe joint body 2 and of a connected portion 10 of each press-ring segment 4A are provided as smooth faces extending along a plane normal to the pipe axis direction X, which faces 40 are fastened to each other in a face-contacted state by bolts 11 and nuts 12 together constituting the fastener means 6. Further, corresponding terminal ends of the peripherally adjacent press-ring segments 4A are joined and fastened to each other by a third connecting means 43 consists of bolts 41 and nuts 42.
With the conventional pipe joint fixing construction described above, when the cam surface 8 formed in the inner peripheral face 4a of the press ring 4 radially reduces or deforms the retainer member 7 either in association with the relative movement between the pipe joint body 2 and the press ring 4 caused by the fastening operation of the fastener means 6 or as a result of an external pulling-out force being applied to the pipe joint body 2 and the fluid transport pipe 1, a corresponding reaction force in a radially outward direction is applied to each segment 4A of the press ring 4. Then, this reaction force may be effectively received in a distributed manner by the bolts 11, nuts 12 constituting the fastener means 6 as well as by the further bolts 41, nuts 42 constituting the third connecting means 43. Accordingly, the construction can effectively restrict diminishing in the bite-in amount of the retainer member 7 which would occur due to the radially outward displacement of the respective press-ring segment 4A.
For achieving the above, however, the construction requires a number of bolts 11, nuts 12 for fastening the respective segments 4A of the press ring 4 and the connecting portion 5 of the pipe joint body 2 along the pipe axis direction X and a number of further bolts 41, nuts 42 for fastening together the terminal ends of the peripherally adjacent press-ring segments 4A. As a result, the assembly operation of the pipe joint was troublesome and time-consuming.